<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title> 实现trim(str)方法，过滤字符串首位空白</title>
</head>
<body>
    <script>
        var reg = /^\s*/
        function trim(str) {
            var ns = str.split(reg)
            return ns[1]
        }
        var test = trim(" 12 5")
        console.log(test)
    </script>
</body>
</html>